Had this extremely pale anomalous tern with a largely dark bill at Girdle Ness yesterday afternoon. Most features at the time shouted Roseate minus the length of the tail and primaries which concerned me... Unfortunately conditions were very windy and didn't see the bird in flight.
Mixed feelings about it elsewhere on the net though a good deal seem to be in favour of Roseate. See here: http://www.birdforum.net/showthread.php?t=230631 . Any help on ID would be much appreciated.